
Low cost audio isolation transformer
LL1591
LL1591 is a low cost audio isolation transformer, pin compatible with e.g. LL1527 and LL1581XL.
The purpose with LL1591 is to provide a low cost solution, when noise rejection requirements are small.
The LL1591 does not have internal faraday shields, nor mu metal housing.
Turns ratio: 1 + 1 : 1 + 1
Pin layout (viewed from component side) and winding schematics:
Spacing between pins Spacing between rows of pins
5.08 mm (0.2") 27.94 mm (1.1")
Dimensions: (L x W x H above PCB, in mm)
37 x 22 x 17
Weight:
39 g
Rec. PCB hole diameter:
1.5 mm
Static resistance of each primary:
43Ω
Static resistance of each secondary:
55Ω
Distortion (primaries connected in series, source
impedance 800Ω ):
+ 6 dBU 0.1% @ 50 Hz
+16 dBU < 1 % @ 50 Hz
Self resonance point :
> 120 kHz
Optimum load for best square-wave response (sec. in
series):
3 – 4 kΩ
Frequency response (source 600Ω , load 10 kΩ serial
connection):
10 Hz -- 80 kHz +/- 1 dB
Loss across transformer (at midband, with above
termination):
0.4 dB
Isolation between windings/ between windings and core: 3 kV / 1.5 kV
Connection alternatives and suggested applications:
Parallel-split connection (1 : 1 + 1)
(In this connection, the transformer picks up external magnetic fields)
Parallel-parallel connection (1 : 1)
(e.g. mic input)
Serial-serial connection (1 : 1)
for line input
Parallel-serial connection (1 : 2)
TRANSFORMERS
Tibeliusgatan 7 International Domestic
S-761 50 NORRTÄLJE Phone +46 - 176 13930 0176-13930
SWEDEN Fax +46 - 176 13935 0176-13935
R050916
LL1591
(top view)